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#DHT

2 public questions tagged with this topic.

Sex determination-l

Which hormone converts testosterone into dihydrotestosterone (DHT)?

Conversion of testosterone into more potent dihydrotestosterone responsible for external genital masculinization is catalyzed not by hormone but by membrane enzyme steroid 5α-reductase type 2 encoded by SRD5A2 gene. Enzyme localized in genital skin, prostate and hair follicles uses NADPH to reduce testosterone double bond forming DHT. DHT binds androgen receptor with higher affinity and slower dissociation ensuring robust activation of male morphogenetic genes. Confusing hormone with enzyme is common, but catalytic step essential. In provided options intended catalyst for external genitalia virilization corresponds to 5α-reductase activity.

Ref: Gilbert, Developmental Biology, 12th ed., Chapter 17: 5α-reductase converts testosterone to DHT.

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sex determination-ll

Enzyme converting testosterone into DHT:

Development of male external genitalia requires local conversion of testosterone secreted by Leydig cells into more active androgen dihydrotestosterone. Reaction catalyzed by microsomal enzyme steroid 5α-reductase type 2 encoded by SRD5A2 gene which uses NADPH to reduce Δ4-5 double bond. DHT exhibits higher affinity for androgen receptor and prolonged receptor-DNA interaction, activating genes for penile growth, urethral closure and scrotal fusion. Deficiency of enzyme causes pseudovaginal perineoscrotal hypospadias despite normal Wolffian ducts, while aromatase converts testosterone to estradiol irrelevant for this masculinization.

Ref: Gilbert, Developmental Biology, 12th ed., Chapter 17: 5α-reductase converts testosterone to DHT.

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